Попробуйте следующее:
<source>
@type dummy
tag dummy
dummy [
{"name": "value", "json": "{\"foo\": \"bar\", \"baz\": 1}"},
{"name": "value", "json": "{\"foo\": \"bar\", \"baz\": 2}"},
{"name": "value", "json": "{\"foo\": \"bar\", \"baz\": 3}"},
{"name": "value", "json": "{\"foo\": \"bar\", \"baz\": 4}"},
{"name": "value", "json": "{\"foo\": \"bar\", \"baz\": 5}"}
]
</source>
<filter dummy>
@type parser
key_name json
reserve_data true
remove_key_name_field true
hash_value_field parsed
<parse>
@type json
</parse>
</filter>
<match dummy>
@type stdout
</match>
Результат:
2019-04-09 12:19:35.042904619 +0900 dummy: {"name":"value","parsed":{"foo":"bar","baz":1}}
2019-04-09 12:19:36.044483191 +0900 dummy: {"name":"value","parsed":{"foo":"bar","baz":2}}
2019-04-09 12:19:37.046293186 +0900 dummy: {"name":"value","parsed":{"foo":"bar","baz":3}}
2019-04-09 12:19:38.048007580 +0900 dummy: {"name":"value","parsed":{"foo":"bar","baz":4}}
См. Последний документ: https://docs.fluentd.org/v1.0/articles/filter_parser#reserve_time